Prolium Bioscience Launches with $50 Million and Announces First Patients Dosed with PRO-203, a Potential Best-in-Class CD20xCD3 T-Cell Engager, for Severe Autoimmune Disease

Prolium生物科学公司启动，获得5000万美元资金，并宣布首个患者接受潜在同类最优CD20xCD3 T细胞结合器PRO-203治疗严重自身免疫疾病。

Initial $50M Series A investment from founding investor RTW Investments

初始的5000万美元A轮融资来自创始投资者RTW Investments。

Proceeds will fund clinical development of PRO-203 in systemic sclerosis (SSc) and multiple additional severe autoimmune diseases

收益将用于资助PRO-203在系统性硬化症（SSc）和多种其他严重自身免疫疾病中的临床开发。

NEW YORK, March 3, 2026-- Prolium Bioscience, Inc. (Prolium), a clinical stage biotechnology company, today announced its launch with a $50 million Series A Financing to develop PRO-203, a potential best-in-class CD20xCD3 T-cell engager, for severe autoimmune disease. The financing was led by its founding investor, RTW Investments (RTW)..

纽约，2026年3月3日 —— Prolium Bioscience, Inc.（Prolium），一家处于临床阶段的生物技术公司，今天宣布完成5000万美元的A轮融资，用于开发PRO-203，一种潜在的同类最优CD20xCD3 T细胞衔接器，针对严重的自身免疫疾病。本轮融资由其创始投资者RTW Investments（RTW）领投。

Prolium announced that it has begun dosing healthy volunteers in an ongoing single ascending dose study of PRO-203 and expects to initiate a multinational Phase 1/2 study of PRO-203 in systemic sclerosis (SSc) in Q2 2026. Additionally, five patients with treatment-refractory, advanced systemic lupus erythematosus (SLE), all of whom also have lupus nephritis (LN), have been treated with PRO-203 in an investigator-initiated study.

Prolium 宣布，已在正在进行的 PRO-203 单次递增剂量研究中开始对健康志愿者进行给药，并预计将在 2026 年第二季度启动 PRO-203 用于系统性硬化症（SSc）的跨国 I/II 期研究。此外，在一项研究者发起的研究中，已有五名患有治疗难治性、晚期系统性红斑狼疮（SLE）且均伴有狼疮性肾炎（LN）的患者接受了 PRO-203 的治疗。

Results will be reported at a future medical conference. Prolium plans to initiate further clinical studies this year in additional severe autoimmune diseases that are driven predominantly by aberrant B-cells. .

结果将在未来的医学会议上公布。Prolium 计划今年在其他主要由异常 B 细胞驱动的严重自身免疫疾病中开展更多的临床研究。

“T-cell engagers are the next frontier in treating autoimmune disease, with the potential to achieve deep B-cell depletion in tissues, like CAR-T, without many of the challenges of CAR-T,” said Scott Requadt, CEO of Prolium. “CD20 is the most well-validated target in B-cell driven autoimmune diseases.

“T细胞结合剂是治疗自身免疫性疾病的下一个前沿，它有潜力像CAR-T一样在组织中实现深度的B细胞耗竭，同时避免CAR-T带来的许多挑战，”Prolium首席执行官Scott Requadt表示。“CD20是B细胞驱动的自身免疫疾病中最被充分验证的靶点。”

Based on promising initial safety and efficacy data, we are excited about the potential of PRO-203 to achieve deep, durable remissions in patients with autoimmune disease and to be an important new therapy for scleroderma and other serious autoimmune diseases.”.

基于令人鼓舞的初步安全性和有效性数据，我们对 PRO-203 在自身免疫疾病患者中实现深度、持久缓解的潜力感到兴奋，并且认为它可能成为系统性硬化症和其他严重自身免疫疾病的重要新疗法。

“PRO-203 has the potential to change the treatment paradigm in scleroderma and other serious autoimmune diseases,” said Peter Fong, Partner and President, RTW. “Prolium’s team is executing impressively to generate substantial data readouts of PRO-203 in several autoimmune disorders within the next two years.”.

“PRO-203 有潜力改变硬皮病和其他严重自身免疫性疾病的治疗模式，”RTW 合伙人兼总裁彼得·冯表示。“Prolium 团队正在出色地执行计划，预计在未来两年内将在多种自身免疫性疾病中生成大量的 PRO-203 数据读数。”

Prolium was founded in 2025 by RTW, which invested $50 million in the company. PRO-203 works by binding both CD20+ B-cells and CD3 on T-cells, forming an immunological synapse around the target cells and recruiting effector T cells to the vicinity of target cells, thereby redirecting T-cells to eradicate B-cells via T-cell dependent cellular cytotoxicity (TDCC).

Prolium由RTW于2025年创立，RTW向该公司投资了5000万美元。PRO-203通过结合CD20+ B细胞和T细胞上的CD3，在目标细胞周围形成免疫突触，并将效应T细胞招募到目标细胞附近，从而引导T细胞通过T细胞依赖性细胞毒性（TDCC）清除B细胞。

The company in-licensed global rights in all non-oncology indications and ex-Asia rights for oncology indications to PRO-203 from KeyMed Biosciences and InnoCare Pharma. PRO-203 has previously been studied in a Phase 1/2 trial in relapsed/refractory Non-Hodgkin Lymphoma (NHL) patients in China, resulting in an overall complete response (CR) rate of 59% and an overall response rate (ORR) of 82% in patients dosed at therapeutic levels..

该公司从键凯生物和诺诚健华获得了PRO-203在所有非肿瘤适应症的全球权利以及肿瘤适应症的亚洲以外权利。PRO-203此前在中国复发/难治性非霍奇金淋巴瘤（NHL）患者中进行了一项1/2期试验，结果显示，在接受治疗剂量的患者中，总体完全缓解率（CR）为59%，总体缓解率（ORR）为82%。

About Prolium

关于Prolium

Prolium Bioscience is a clinical stage company developing PRO-203, a potential best-in-class, bispecific CD20xCD3 antibody for systemic sclerosis and other severe autoimmune diseases. Founded and backed by RTW Investments, Prolium has assembled a team with deep experience in the development of therapeutics in autoimmune disease.

Prolium Bioscience是一家临床阶段的公司，正在开发PRO-203，一种潜在的同类最佳、双特异性CD20xCD3抗体，用于治疗系统性硬化症和其他严重的自身免疫疾病。Prolium由RTW Investments创立并支持，组建了一支在自身免疫疾病治疗药物开发方面拥有深厚经验的团队。

For more information about Prolium, please visit www.proliumbio.com..

有关 Prolium 的更多信息，请访问 www.proliumbio.com。

About RTW Investments, LP

关于RTW投资有限公司

RTW Investments, LP is a New York-based, global, full life-cycle investment firm that focuses on identifying transformational and disruptive innovations across the biopharmaceutical and medical technologies sectors. As a leading partner of industry and academia, RTW combines deep scientific expertise with a solution-oriented investment approach to advance emerging therapies by building and supporting the companies developing them.

RTW Investments, LP是一家总部位于纽约的全球全生命周期投资公司，专注于发现生物制药和医疗技术领域的变革性和颠覆性创新。作为业界和学术界的领先合作伙伴，RTW结合深厚的科学专业知识与以解决方案为导向的投资方法，通过构建和支持开发这些疗法的公司来推动新兴治疗手段的发展。

For further information about RTW, please visit www.rtwfunds.com.

有关 RTW 的更多信息，请访问 www.rtwfunds.com。

Contact:

联系：

Investor & Media Contact:

投资者和媒体联系：

Chris Brinzey

克里斯·布林齐

ICR Healthcare

ICR医疗保健

Chris.Brinzey@icrhealthcare.com

克里斯·布林齐@icrhealthcare.com